Directional indication and control



June 20, 1939.

L. DE FLOREZ DIRECTIONAL INDICATION AND CONTROL Filed Aug. 28, 1936 AT ORNEY Patented June 20, 1939 UNITED STATES 2,162,940 DIRECTIQNAL INDICATION CONTROL Luis 'de Florez, New York, N. Y., assignor to National Aviation Research Corporation, New York, N. Y., a corporation of Delaware Application August 28,1936, Serial No. 98,352

8 Claims.

This invention relates to directional indication and control. More specifically, it relates to the directional indication and control of various types of moving craft and more particularly aircraft.

In view of the inherent stability characteristics, modern aircraft can be flown and maintained on a course, practically by rudder control alone. i

The broad objects of this invention are to provide a mechanical system readily applicable to the modern airplane and adapted either or both to indicate deviations from course and to automatically return the ship to or maintain it on the proper course.

Various methods of control have been proposed heretofore; includingelectrical and pneumatic systems, and combinations of both. For the most part, these have been heavy and complicated and too expensive for ordinary adoption. Furthermore, difliculties have been experienced in the matter of over-control. If the system was sufficiently responsive, the tendency was to over-correct, calling for immediate correction in the opposite direction and setting up a hunt-.-

ing efiect, causing theship to swing first to one side and then to the other, instead of maintaining the true course.

' This swinging efiect is particularly pronounced with simple, pneumatic control systems, the off- 30 course movement having-a tendency to initiate a series of accelerating or ever-increasing sideto-side oscillations.

Special objects of the present invention are toprovide a simple and reliable form of pneumatic equipment for control and indication purposes, inexpensive enough for general adoption and which will maintain stable on course direction, without the objectionable hunting or swinging effect above mentioned.

4o attained in this invention by the novel features of construction, combinations and relations of parts The foregoing and other desirable objects are Figure 2 is an enlarged broken sectional detail of the gyroscopically controlled air valve. Figure 3 is a broken part sectional view of the booster valve controlled by the gyro valve.

Figure 4 is a broken cross sectional detail'on 5 substantially the plane of line 4-4 of Figure 3. In Figure 1 a rate. of turn sensitive instrument is indicated in the form of gyroscope I pivotedat 8 on the longitudinal axis or parallel to the longitudinal axis of the craft so that with turn 10 in one direction or the other it will rock to cause the arm 9 to swing left or right. This arm carries a pin Ill engaging between parallel pinsll dependent from rock shaft l2 journaled in casing l3 of the air control valve.

Details of the sensitive control valve are shown in Figure 2, where avalve element is indicated' at ll, carried byshaft l2 and operating freely in a cylindrical valve chamber l5. This valve element is shown as having segmental recesses l6, H, in oppositesides of the same adapted in the intermediate position shown, to register equally with top and bottomportsl8, l9 and 20 2|, as well as with the intermediate side ports 22, 23 in the valve casing. The upper pair of ports I8, 20 lead from an arcuate top chamber 24 which opens to atmosphere through a suitable air filter 25. The lower ports l9, 2| lead from an arcuate chamber 26 which is connected by suction tubing 21 with a venturi 28. The two side 30 ports 22, 23 are connected by tubing 29, 30 with the opposite ends of the monitor or booster valve 3| and with the rate of turngage 32 and the integrating turn gage 33.

From the description thus far it will be evi- 35 dent that tuning of the valve element It by the gyro, say in a right-handed direction, Figure 2, will have the effect of fully opening port l8 and closing port 20 at the top and closing port l9 while fully opening port 2|. at the bottom, resulting in the line 29 at the left being connected with atmospheric chamber 24 and cut ofi from suction chamber 26 and line 30 at the right being cut of! from atmospheric chamber 24 and fully connected with suction chamber 26. Thus, pressure in the right-hand line will be reduced, while pressure in the left-hand line will be restored to atmospheric or approximately so. Reverse rotation of the valve element will have the reverse effect,- reducing pressure in the line 29, while admitting atmospheric pressure to line 30.

The booster valve 3| is shown in Figures 3'and 4 as consisting ofa piston valv'e element 34 having an intermediate valve head 35 controlling spaced suction ports 36, 31, and one end head 38 controlling ports 33 and an opposite end head 40 controlling ports 4|. Ports 33 and 4| provide communication between the chamber 42 and spaces 43, 44, between thevalve heads and respectively connected by tubing 43, 46 with the opposite ends of the servomotor cylinder 41 in which operates piston 43, connected at opposite sides by cables 43, 33 with the rudder 5|. The chamber 42 in the booster valve is open to atmosphere through an air filter similar to that shown at 25, Figure 1, and. consisting of a tubular stud -52 screwed into chamber 42 and having outstanding spaced perforated flanges 63, 54 with filter material 56 therebetween. A cap 56 engaged over these flanges forces the air to enter through perforations in the base flange 53, pass through the filter material and thence through the outer flange 54 and down the passage in the tubular stud into the chamber.

In the intermediate position indicated in Figure 3, the middle valve head 36 opens the suction ports 36, 31 equally to the chambers 43, 44 in communication by piping 43, '46, with opposite ends of the servomotor and the end valve heads 33 and 40 open the ports 33, 4| equally to the spaces 43, 44, so that pressure on opposite sides of the servomotor piston is equalized for holding the rudder in an intermediate position.

The valve element 34 of the booster is reversely acted on by diaphragms 61, 33 in chambers 63, 66 at opposite. ends of the valve casing and connected respectively with tubing 23, 36 from the control valve. These diaphragms are shown as pressed toward each other by springs 6|, 62 and the latter is indicated as adjustably tensioned by hand screw 63. A rod 64 is connected at opposite ends-with the two diaphragms and extends loosely through the valve element 34. 'I'he-left-hand*'diaphragm is shown as having a'hub 65 providing'an abutment for the adjoining end of the valve element and a spring 36 is shown interposed between the other diaphragm and the opposite end of the valve. By this construction the valve is enabled to move freely andsmoothly under. the slightest impulse from the diaphragms, one way, or the other. Thus, sensitive valve movement is eflected, without any binding or cramping effects from the diaphragms.

To overcome the hunting and swinging tendencies to which systems of this character haveheretofore been subject, orifices or restrictions are placed in the lines and cushions in the nature of volumetric capacities are connected with the lines. g

In .the particular example given in Figure 1,

variable orifices are located in lines 23, 30,'in

the form of needle valves 66, 61 and closed tanks 63, 63' are connected with the ends of these lines. In-the lines 23a, 36a extended to the integrating turn gage 33, restrictions are interposed in the form of capillary tubes 16, 1| and these extended lines have the closed tanks .12, 13 connected therewith.

- The rate of turn gage 32 and the integrating turn gage 33 may be simple differential gage instruments, the first subjected to the varying differ ential pressure in lines 23, 30 controlled by the gyro 'valve and showing directly the rate of turnand the second subjected to these same pressures, through 'the restrictions and capacity tanks and integrating the rate of turn accordingly.

In operation, as a turn is started, the gyroscope will rotate the valve element I4, Figure 2,

one way or the other, to apply greater suction through one line 23 or" to one or the other diaphragm 61, I3 ofthe booster valve and to accordingly shift valve element 34, Figure 3, to variably apply suction to one side and atmospheric pressure to the other side of the servomotor piston 43 through lines 43, 46, thus to eflect adjustment of the rudder for bringing the ship out of the turn and back on the course.

The rate of turn gage 32 being directly subjected to the diiferential pressures in lines" and 33 eflected by the control valve, shows immediately the rate of turn and the return back to course. The fiow restricting adjustable orifices 66, 61 in the lines 23, 33 reduce the rate of correction at the booster valve diaphragms sufflciently to prevent over-correction and this compensating or correctional control isfurther effected by the ,so-called vacuum accumulator ditions. By adjustment of orifices 66, 61, the

timing of these corrective'forces can be accurately regulated to bring the ship back to the correct course with the desired rapidity and without appreciable or objectionable over-swing.

The efi'ect at the integrating turn gage 33 is generally similar, the capillary tubes 10, 1| having a restrictive 'eflec't, delaying movement of. the needle and the vacuum tanks 12, 13 having a capacity eflect enabling this meter to integrate turn movements. As a practical example,-the rate'of turn indicator at 32 responding instantly to turn movements, may show immediate turns and returns to course while the integrating gage will give a straight on-course indication, constituting the average or "mean" directional movement of the plane.

The mechanism may be immediately equalized for a new course by directly connecting the two differential lines 23, 36, as by means of a cross connection 14 having a hand valve 16, Upon opening this valve the diiferential lines will be balanced and then .with the turn to the new course manually completed by the pilot and the gyro stable on the new course, this valve may be closed to again put the gyro and pneumatic system in control.

Also, in the illustration, the servomotor may be immediately cut out of action at any time by a cross connection shown at 16, Figure 1, containing a hand cook 11 which may be turned to couple the opposite ends of the servomotor cylinder together so that piston 43 will not impede manual adjustments of the rudder. Further, to prevent this piston of the motor or power cylinder from acting as a drag in case of a sudden, necessary rudder adjustment by the pilot, said a 'piston may have reversely acting spring closed 1 The rubber or other flexible couplings 34 in the tubes 21, 23, 33. P rmit such adjustments of the valve casing. By proper'setting at this point,'

40 i and motor comprisingdifferential pressure valve means interposed between said fluid pressure 7 the control valve will be enabled to keep the plane on a straight course, or if desired, on a curved course. Equivalent results are obtainable by adjustment of the spring 62 for adjusting spring tension on the diaphragm 58, Figure 3, of the booster valve.

While the venturi provides a desirable form of pressure creating means it will be realized that a pump or the like may be used instead as a means for creating either a negative or positive pressure for operation of the system. The booster valve is of advantage where operation of the rudder may require considerable power,

but in smaller installations, the booster valve may be eliminated and the differential connections from the control valve be direct to the servomotor, for which instance the differential lines 29, 3|] may be considered as directly connected with lines 45, 46, instead of indirectly through the booster valve. The valved line 14 for equalizing the two differential pressure lines 29, 30 may be considered simply as a bypass for short-circuiting the control valve lines.

I claim:

1. Automatic control for aircraft comprising a turn sensitive device, fluid pressure creating means, directional controlling means, differential fluid pressure mechanism for operating said directional controlling means, valve means operable by said turn sensitive means for differentially connecting said differential mechanism with said fluid pressure creating means, means restricting the flow between said first means and said mechanism, fluid accumulator tanks operatively connected betweensaid first means and said mechanism.

2. Automatic control for aircraft and the like comprising in combination with a fluid differential pressure directional control motor, a fluid pressure source, means connecting said source source and said differential pressure motor, directional sensitive means for actuating said differential valve means and means for damping said differential pressure changes including pressure differential tanks in communication with and pressure differential accumulator tanks in communication with said connecting means.

valve means operable by said directional sensi-' tive instrument, said pressure source being connected with said differential pressure valve means, a differential pressure gage connected for differential operation by said valve means, a second integrating differential pressure gage connected in parallel with said first gage and second integrating gage.

5. In combination, a directional sensitive instrument, a pressure source, differential pressure valve means operable by said directional sensitive instrument, said pressure source being connected with said differential pressure valve means, a differential pressure gage connected for differential operation by said valve means, a second integrating differential pressure gage connected in parallel with said flrst'gage and flow restrictive means in the connections to said second integrating gage, said flow restrictive means comprising capillary tubing.

6. In combination, a directional sensitive instrument, a pressure source, diiferential pressure valve means operable by said directional sensitive instrument, said pressure source being connected with said differential pressure valve means, a differential pressure gage connected for differential operation by said valve means,

ond integrating gage and accumulator tanks in connection with said second integrating gage.

7. In combination, a pneumatic directional controlling servomotor, a pneumatically actuated booster valve connected to control said servomotor, a control valve, a venturi connected with said control valve and with said booster valve, differential pressure control lines from said control valve to said booster valve, a directional sensitive instrument governing operation of said control valve and means connected with said differential pressure lines for preventing over-control of said servomotor, including fluid pressure restrictive and accumulator means.

8. Automatic control for aircraft, comprising flow restrictive means in the connections to said in combination, a fluid differential pressure directional control motor, a fluid pressure source, means connecting said fluid pressure source and said differential pressure control motor comprising differential pressure valve means and difierential pressure connections between said valve means and motor, directional sensitive means for controlling said differential valve means, fluid pressure accumulator tanks of fixed capacity connected with the respective differential pressure connections and flow restrictive valve means in the individual differential pressure connecential pressure connections. I

LUIS or: FLOREZ. 

